Actuator assembly for toggle switch

ABSTRACT

Actuator assembly for snap action toggle switch has a rockerlike actuator member which is pivoted on a transverse axis. A roller mounted on the actuator member is adapted to be engaged for overcenter movement of the actuator at a point spaced from the pivot axis of the actuator member by a member on the end of the toggle lever having a curved outer surface resiliently biased into engagement with the roller. By the use of a pair of curved cooperating surfaces to cause overcenter movement, at least one of which is a roller, which contact each other intermediate their respective pivot mountings, a very unstable teaseproof mounting is provided.

United States Patent Inventor Edward L. Barrett La Grange Park, 111.Appl. No. 881,049 Filed Dec. 1, 1969 Patented Aug. 10, 1971 Assigneelllino'm Tool Works Inc. Chicago, Ill.

ACTUATOR ASSEMBLY FOR TOGGLE SWITCH 4 Claims, 4 Drawing Figs.

References Cited UNITED STATES PATENTS 2,961,505 11/1960 Alio et a1.200/68 UX 2,972,663 2/1961 Zanichkowsk et a1. 200/68 X 3,351,729 11/1967Bergman 200/68 X FOREIGN PATENTS 1,306,612 9/1962 France ..200/67 D (UX)Primary Examiner-David Smith, Jr. Att0rneys-Robert W. Beart, MichaelKovac, Barry L. Clark and Jack R. Halvorsen ABSTRACT: Actuator assemblyfor snap action toggle switch has a rockerlike actuator member which ispivoted on a transverse axis. A roller mounted on the actuator member isadapted to be engaged for overcenter movement of the actuator at a pointspaced from the pivot axis of the actuator member by a member on the endof the toggle lever having a curved outer surface resiliently biasedinto engagement with the roller. By the use of a pair of curvedcooperating surfaces to cause overcenter movement, at least one of whichis a 2,633,510 3/1953 Schellman 200/68 roller, which contact each otherintermediate their respective 2,769,050 10/1956 Boume ZOO/67.7 UX pivotmountings, a very unstable teaseproof mounting is pro- 2,780,691 2/1957Landin ZOO/67.7 UX vided.

,1: 48 I g l I/ I I I I I I I I l 64 62 1 64 52 1 l 54 I X i 70 60 I r T58 4o 0 74 5 I L .\..Li

24 I4 I I r," 26

ACTUATOR ASSEMBLY FOR TOGGLE SWITCH BACKGROUND OF THE INVENTION 1. Fieldof the Invention This invention relates to electrical switches andparticularly to an actuator assembly for a snap action toggle switchwhich is teaseproof.

2. Description of the Prior Art Electrical toggle switcheshaving aspring-biased roller type of cam follower on the toggle lever have beenused to cause a rocking movement of a pivoted actuator member having acam surface thereon engageable with the roller to cause an overcentermovement of the actuator as shown in Landin U.S.

Pat. No. 2,780,691 or Puccini U.S. Pat. No. 3,322,914. Since the pivotaxes for the toggle lever and for the rocking actuator member in LandinU.S. Pat. No. 2,780,691 are both on one side of the point of contactbetween the roller and cam surface the actuator assembly would not be asunstable or resistant to teasing as would be an assembly wherein therespective roller and cam-contacting surfaces were intermediate thepivot points of the two pivoted members. Schellman U.S. Pat. No.2,633,510 shows a roller in association with a contact member whereinthe mounting for the roller is not pivoted but is mounted on one end ofa spring. The roller member in Schellman would have no positiveovercenter position since its wobbly spring mounting would cause itseffective pivot point to shift with the changes in loading applied tothe anchored end of the spring as it is bent.

SUMMARY The toggle-type actuator assembly of the present inventionincludes a toggle lever pivotally mounted in the cover of a switchhousing and a cradlelike actuator member pivotally rockable about anaxis transverse of its length in a U-shaped support bracket affixed tothe bottom of the switch housing. The ends of the actuator member maycarry movable switch contacts which are adapted to contact fixed switchcontacts in the housing. In a modified form of the invention, the endsof the cradlelike actuator member may be used to depress thepushbuttonsof one or more switches affixed to the housing.

The actuator member is formed with a pair of upwardly extendingtrunnions which cradle and support the shaft of a roller mounted thereinin such a manner that the axis of the roller is positioned parallel tothe pivot axis of the actuator member and in a plane generallyperpendicular to the general plane of the actuator which includes thepivot axis of the actuator. The roller on the actuator member is adaptedto be engaged, to cause overcenter movement of the actuator member, by aspring-loaded cam member which is telescopically mounted within thetoggle lever. The cam member on the toggle lever may be of variousshapes such as, for example, a bullet-nosed member which is biased intocontact with the roller at all times. When the cam member in the togglelever is moved, by movement of the toggle lever, past a line connectingthe actuator member pivot axis, and the roller pivot axis, it will causean overcenter snap movement of the roller and actuator member about theactuator member pivot axis which will drive the actuator member to itsopposite extreme position. Due to the presence of the roller member onthe actuator, the mechanism is extremely teaseproof since the rollerwill roll as the cam member on the toggle lever is moved along itssurface. By having the pivot axis for the actuator member and the pivotaxis for the toggle lever positioned at points on opposite sides of thepoint of contact between the cam member and the roller member, theassembly is extremely unstable from the standpoint that it is almostimpossible to tease as compared to having both pivot axes on the sameside of the point of contact.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view of aswitch housing incorporating the improved actuator assembly taken on theline l-l of FIG. 2, except that the working parts other than the togglelever are left whole;

FIG. 2 is an end sectional view taken on the line 2-2 of FIG.

FIG. 3 is an exploded view showing the relationship between the roller,the actuator member and the actuator member support bracket; and

FIG. 4 is a diagrammatical side view of a modified form of actuatorassembly wherein the actuator member operates the pushbuttons for aplurality of switches rather than carrying self-contacts as in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, the improved actuatorassembly indicated generally at 10 is mounted in a switch housingindicated generally at 12 which supports a pair of fixed contacts l4, 16which are respectively integrally fastened to external terminal members18, 20. A common terminal element 22 is affixed to the housing and to agenerally U-shaped bracket 24 therein by means of a rivet 26. TheU-shaped bracket member 24 has a pair of inwardly projectingdeformations 28 which comprise pivot centers adapted to be engaged bymating depressions 30 formed in the opposite sides of actuator member32. Arranged centrally of the actuator member 32 and attached thereto isa cradle support bracket 34 having a pair of trunnions 36 which engagethe shaft ends 38 of a roller member 40. Movable contact members 42, 44are attached at opposite ends of the actuator member 32 for selectiveengagement with the fixed contact members 14, 16.

A toggle lever 48 for operating the switch is pivotally mounted in theswitch cover member indicated generally at 50. The cover member 50comprises an upper plate member 52 having upwardly extending sphericallyshaped deformations 54 for engaging a spherical surface 56 formed on thetoggle lever. Attached to the upper plate member 52 is a lower platemember 58 having downwardly extending spherically shaped deformedportions 60 adapted to engage the lower portion of the spherical surface56 on the toggle lever 48. In order to maintain a firm mounting for thespherical portion 56 of the toggle lever 48 in plates 52, 58, astrip ofresilient material 62 such as rubber is positioned between the plates 52and 58 to permit the spherical deformations 54 and 60 to be maintainedin slight compressive relationship with the toggle lever. The layers 52,58 and 62 of the cover 50 may be held together by means such as rivets64. Mounted in telescopic relationship with the toggle lever 48 is abullet nosed fiber cam member 70 including a conical cam surface 72terminating at its end in a spherical tip portion 74.

In operation of the actuator assembly, the toggle lever is pivoted fromits solid line position shown in FIG. 1 to the second dotted positionshown. During this movement, the cam member 70 is moved upwardly againstthe force of spring 76 as cam surface 72 moves upwardly along thesurface of roller 40. Since the roller 40 has its shaft mounted intrunnions 36, it is free to rotate as cam surfaces 72 and 74 move overit with very little friction being produced to counteract the move mentof toggle lever 48. Furthermore, the lifting of the cam member 70against the force of spring 76 will increase the force exerted on theroller 40 and the actuator 32 which in turn will tend to increase theforce with which movable contact 42 bears on fixed contact 14. Thisincreased force on the contacts will be released instantaneously and themovable contact 44 will be snapped into engagement with fixed contact 16as the point of tangency between cam tip 74 and roller 40 passes throughthe point a on the roller. Point a is the overcenter point at which thepoint of tangency is in line with the line b which passes through theaxis of the actuator pivot 28 and the roller shaft 38. By insuring thatthe contact force does not drop off during a switching operation, theswitch can provide long operational life without arcing.

By mounting roller 40, as shown in FIG. 1, so that the axis of itssupport shaft 38 and its point of tangency a with the cam surface 74 isintermediate the pivot point for the toggle lever 48 and the actuatorpivot point 28, the cam member 70 and the roller 40 are in an extremelyunstable relationship to each other as cam tip 74 approaches the line bat which the actuator member 32 will snap overcenter. This unstablesituation is enhanced by the fact that the cam member 70 is at itsextreme upward position at this time so that it exerts the most springforce on the roller. Furthermore, since each of the surfaces 74 and 40are curved and in rolling contact as they pass line b, there is nosliding friction present to impede the snap action of the actuatormember 32 as would be the case if the respective contacting members werein sliding rather than rolling relationship.

in FIG. 4, the actuator assembly of the invention is diagrammaticallyshown in association with a pair of pushbutton switches'80, 82 havingpushbuttons 84, 86 respectively, for operating the electrical contactswithin them. Since certain users of switches specify that the axis ofthe toggle lever point to the contacts which are closed (a condition notmet by the embodiment of FIG. 1 wherein pivot axis 28 is below, ratherthan above the axis of roller shaft 38), it should be noted that theembodiment of FIG. 4 wherein the actuator member 32 merely actuatesother switches rather than carrying contacts could be used since theswitches 80, 82 can readily be obtained with contacts which are eitherin a normally open or a normally closed position.

lclaim:

1. In an actuator assembly for making and breaking the contacts of anelectric switch having a housing, a toggle lever member pivoted in thehousing and an actuator member pivoted in the housing and engageable bythe toggle lever to cause the switch contacts to be moved relative toeach other,

the improvement comprising: pivot means mounted in said housing forsupporting said actuator member, at least one roller mounted on saidactuator member for rotational movement about an axis thereon spaced ata fixeddistance from the axis of said pivot means for said actuatormember, the axis of the roller being positioned intermediate acooperating member for engaging the roller and the axis of the actuatormember pivot means, said cooperating member being resiliently biasedinto engagement with said actuator member and mounted for movement onthe toggle lever in the direction of the length of the toggle lever,said cooperating member having a generally conical shape terminating ina generally spherically shaped apex tip which is resiliently biased intocontinuous rolling engagement with said roller on said actuator memberand adapted to rock said actuator in one direction or the other as itmoves past a point on said at least one roller which is in line with theaxis of the roller and the axis of said pivot means.

2. An actuator assembly as defined in claim 1 wherein said actuatormember comprises arocking plate carrying a contact at at least one ofits ends, said contact on said rocking plate being movable into and outof engagement with a fixed contact mounted in the housing.

3. An actuator assembly as defined in claim 2 wherein said rocking platehas contacts on each of its ends adapted to be brought into alternateengagement with a pair of cooperating fixed contacts in thehousing.

4. An actuator assembly as defined in claim 3 wherein the rocking planeis mounted within a U-shaped bracket member having a pair of inwardlyprojecting spherical deformations defining pivot centers which areengaged by mating depressions formed on opposite sides of the actuatormember.

1. In an actuator assembly for making and breaking the contacts of anelectric switch having a housing, a toggle lever member pivoted in thehousing and an actuator member pivoted in the housing and engageable bythe toggle lever to cause the switch contacts to be moved relative toeach other, the improvement comprising: pivot means mounted in saidhousing for supporting said actuator member, at least one roller mountedon said actuator member for rotational movement about an axis thereonspaced at a fixed distance from the axis of said pivot means for saidactuator member, the axis of the roller being positioned intermediate acooperating member for engaging the roller and the axis of the actuatormember pivot means, said cooperating member being resiliently biasedinto engagement with said actuator member and mounted for movement onthe toggle lever in the direction of the length of the toggle lever,said cooperating member having a generally conical shape terminating ina generally spherically shaped apex tip which is resiliently biased intocontinuous rolling engagement with said roller on said Actuator memberand adapted to rock said actuator in one direction or the other as itmoves past a point on said at least one roller which is in line with theaxis of the roller and the axis of said pivot means.
 2. An actuatorassembly as defined in claim 1 wherein said actuator member comprises arocking plate carrying a contact at at least one of its ends, saidcontact on said rocking plate being movable into and out of engagementwith a fixed contact mounted in the housing.
 3. An actuator assembly asdefined in claim 2 wherein said rocking plate has contacts on each ofits ends adapted to be brought into alternate engagement with a pair ofcooperating fixed contacts in the housing.
 4. An actuator assembly asdefined in claim 3 wherein the rocking plane is mounted within aU-shaped bracket member having a pair of inwardly projecting sphericaldeformations defining pivot centers which are engaged by matingdepressions formed on opposite sides of the actuator member.